Electromagnetic switching device

ABSTRACT

In the electromagnetic switching device, it is possible to miniaturize and have low costs, have quiet operation noise, and also quickly extinguish the arc. The electromagnetic switching device has an electromagnetic actuator with a movable iron core, a pair of fixed terminals that respectively have a fixed contact point, a movable contact that has movable contact points on the right and left ends, a shaft, and an enclosing component that holds the movable contact points and the fixed contact points. The pair of movable contact points respectively contact with and detach from the pair of fixed contact points, and the pair of fixed contact points respectively conduct each other and are insulated again through the shaft by moving the movable iron core along the axis using the electric magnetic actuator. A quasi-hermetically sealed space, which is the extinguishing space, is formed by the enclosing component and a first yoke. A potting compound is charged, into the space between a body and the quasi hermitically sealed space.

FIELD OF THE INVENTION

The present invention relates to an electromagnetic switching device tomake or break a circuit in an electric drive mobile object e.g.

BACKGROUND OF THE INVENTION

Conventionally, in electromagnetic switching devices, some of them havebeen used for the purpose of making and breaking an electric powercircuit of a vehicle, using the format whereby the contact mechanism isoperated by opening and closing with an electromagnetic actuator. Asexamples of these types of electromagnetic switching devices, the onesshown in FIGS. 19, 20 and 21 are well known. These types of examplesinclude the Japanese Patent Laid-Open Publication No. 2002-42628.

This electromagnetic switching device consists of a body 11 made ofresin (plastic), an electromagnetic actuator 2, a pair of fixedterminals 3, a movable contact 4, a shaft 5, etc. as shown in theFigure.

The body 11 is formed into a box shape that is cut in half, and the mainbody of the electromagnetic switching device is placed inside. The body11 has mountings 13 on the right and left sides (the same as the rightand left sides in the Figure) to fix the electromagnetic switchingdevice to the external attaching part. Also, the body 11 has a lead-outgroove (not shown in the Figure) to expose the terminal area 31 of thefixed terminals 3 from the inside to the outside in order to connect itto an external circuit.

The electromagnetic actuator 2 consists of a solenoid coil, top andbottom yokes (the same top and bottom as in the Figure), a movable ironcore, etc. The solenoid coil 21 consists of a cylindrical bobbin 21 a,which has flanges on the top and bottom, with the conducting wire woundaround it, and both ends of the conducting wire are led to the outsideof the body 11 (not shown in the Figure). A first yoke 23 is placed fromthe middle of the inner circumference surface to the upper surface ofthe solenoid coil 21, and a second yoke 24 is placed from the lower partof the inner circumference surface to the bottom surface and the outercircumference surface of the solenoid coil 21, and these, the first yoke23 and the second yoke 24, form the magnetic gap with the magnetic polesfacing each other inside the solenoid coil as well as the magnetic path.

A movable iron core 22 has a part of itself intervening in the magneticgap mentioned above, and has the rest of itself in the internalcylindrical part of the second yoke 24. Also, the movable iron core 22is biased to the direction such that the magnetic gap can be made larger(to the bottom of the Figure) by a coil spring 22 a. Therefore, when thesolenoid coil 21 is excited, the movable iron core 22 moves up in orderto lessen the magnetic gap, and when the excitation is stopped, it movesdown by the coil spring 22 a.

The fixed terminal 3 is built with the rectangular shaped conductiveplate bent twice in a same direction and both ends turned in a samedirection. The fixed terminal 3 has the terminal area 31 outside of thebody 11 and has a fixed contact point 32 facing downward inside the body11 as well.

The movable contact 4 is built to have movable contact points 41 eachrespectively facing opposite to said fixed contact points 32 on bothends of the rectangular shaped long conductive plate with the centerpart bent downward, and it is fixed under a retentive part 51 that isformed on the upper part of the shaft 5. The movable contact 4 is pushedup against the headliner of the retentive part 51 by contact pressuresprings 41 a under the retentive part 51.

The shaft 5 has the bottom end of the connecting axis that extendsdownward from said retentive part 51 and is fixed into the movable ironcore 22, and is placed on the central axis of the electromagneticactuator 2. The shaft 5 is movable up and down within a specified rangeinside the electromagnetic actuator 2. The lowest limit of the movementis the point where the bump of the diameter expansion part of the shaft5 contacts with the insertion hole on the central axis of the first yoke23, and the cushioning component 53 a is placed on the contact point.Additionally, the upper limit of the movement is the point where theupper end of the movable iron core 22 contacts with the lower end of thefirst yoke 23.

On the lateral side that is outside the body 11 and that the fixedcontact points 32 and the movable contact points 41 contact and detach,a yoke 64 that forms the magnetic path and a pair of permanent magnets65 for generating the magnetic field are placed. The permanent magnets65 are placed with the magnetic poles facing each other in order toquickly extinguish an arc, which is generated when the fixed contactpoints 32 and the movable contact points 41 contact and detach, by themagnetic field of the permanent magnets.

When the electromagnetic switching device with the mechanism describedabove is brought into action and the movable iron core 22 is moved upand down by the electromagnetic actuator 2, the pair of movable contactpoints 41 of the movable contact 4 each respectively contact with anddetach from the pair of fixed contact points 32 through the shaft 5 thatmoves up and down. Because of this, the circuit between the terminalareas 31 on the pair of fixed terminals 3 is electrically opened andclosed through the movable contact 4.

However, because the existing electromagnetic switching devicesmentioned above have space (extinguishing space SP) to scatter theenergy of the arc by stretching the arc spatially for the purpose ofquickly extinguishing the arc generated at the time of opening andclosing of the circuit, there is a problem that it is difficult tominiaturize the electromagnetic switching devices. Because the spacearound the solenoid coil 21 is to be used as the space for extinguishingthe arc, there is a possibility of the arc approaching the winding wireof the solenoid coil 21, and it is preferable to avoid this type ofmechanism in order to maintain the insulation performance between thecircuit side opened and closed (the primary side) and the controllingside of the electromagnetic switching device (the secondary side).

In addition, the arc is occasionally brought into contact with the resinof the body 11 to generate an extinguishing gas, and in this case,because it is necessary to enclose the extinguishing space with theresinous component that generates the extinguishing gas, there is alimit in miniaturizing the electromagnetic switching device. Also, whenthe electromagnetic switching device is used for electric vehicles, itis preferred to decrease further the operating noise of theelectromagnetic switching device, etc. in order to keep the environmentinside the vehicles preferable. This is because the motor that directlygenerates turning force is used as the drive source and the drive sourceis quiet unlike the existing petrol engine, etc. that uses explosiveburnings as the drive force.

This invention aims at providing an electromagnetic switching devicethat can be miniaturized, can be made at low cost and is quiet, as wellas being able to extinguish the arc quickly.

DISCLOSURE OF THE INVENTION

To achieve the purpose mentioned above, the electromagnetic switchingdevice according to the present invention comprises: an electromagneticactuator which has a solenoid coil wound around one axis and havinghollow part on the axis, a movable iron core placed movably along saidaxis in said hollowing part, a first yoke placed on one of the ends ofsaid solenoid coil, facing to one of the ends of said axis, and havingan insertion hole on said axis, and a second yoke placed on the otherend of said solenoid coil, facing to the other end of said axis; a pairof fixed terminals respectively having a fixed contact on one of theends of said axis as well as the terminal area, which connects to theexternal circuit, on the other end of said axis; a movable contacthaving a pair of movable contact points, which respectively contact withand detach from said fixed contact points, on both ends; a shaft havinga connecting axis which is fixed to a retentive part holding saidmovable contact, extends from this retentive part to the other end ofsaid axis, is inserted into the insertion hole of said first yoke, andis fixed to said movable iron core; and an enclosing component, whichcontains said movable contact points and said fixed contact points.

In the electromagnetic switching device of this invention, by movingsaid movable iron core along said axis using said electromagneticactuator, the pair of said movable contact points respectively contactwith and detach from the pair of said fixed contact points through saidshaft, and the enclosing component is formed into a box shape with anopening on the other side of said axis, and each of the fixed contactpoints sides of the pair of said fixed terminals is inserted from thebottom part of the enclosing component and is fixed. Aquasi-hermetically sealed space is formed by the enclosing component andat least said first yoke, and said movable contact points and said fixedcontact points are placed in the quasi-hermetically sealed space.

With this type of mechanism, because the quasi-hermetically sealed spaceis formed by the enclosing component and at least the first yoke, andthe movable contact points and the fixed contact points are placed inthe quasi-hermetically sealed space, it is possible to miniaturize theextinguishing space and to maintain the extinction performance. Thus, itbecomes possible to miniaturize the electromagnetic switching device. Inother words, it is possible to increase the capability to cool off thearc (to absorb the energy) because metals have good heat conductancecompared to molding materials (resin). In this regard, because the firstyoke made of metals is used as a constructional component for thequasi-hermetically sealed space, the extinction performance improves andrapid blocking of the contact points becomes possible. Also, it ispossible to share the components of the electromagnetic switching deviceand to miniaturize, thereby reducing the cost by reducing the number ofcomponents of the electromagnetic switching device. Becauseextinguishing space is constituted within the quasi-hermetically sealedspace, the arc does not leak to the outside of this space or damage thesolenoid coil of the electromagnetic switching device, and it ispossible to maintain the insulation performance between the circuit sidethat is opened and closed (the primary side) and the controlling side ofthe electromagnetic switching device (the secondary side.)

In the improved invention described above, it is preferable that thisinvention has a body that holds the main body of the electromagneticswitching device with said terminal area projected outward, and that thespace between said body and said quasi-hermetically sealed space isfilled with a potting compound. With this type of mechanism, because thepotting compound is charged into the space between the body and thequasi-hermetically sealed space, it is possible to quickly cool down theconstructional components of the quasi-hermitically sealed space (theenclosing component and at least the first yoke) that are heated by thearc generated between the contact points. This can be done by using acompound that has good heat conductance as a potting compound.Therefore, it is possible to block the arc by quickly absorbing the heatenergy of the arc. Also, because the potting compound restrains thepropagation of the vibration that occurs from the inside of the mainbody of the electromagnetic switching device to the body, a silencingeffect can be obtained. By using the potting compound, a coveringcomponent is not needed and the body can be built with only onecomponent. This enables the lowering of costs.

In the improved invention described above, it is preferable that thedistance between an inside wall of said enclosing component and saidmovable contact is narrow at the part that is near said shaft, and iswider at the part that is far from said shaft. With this type ofmechanism, because the distance between the inside wall of the enclosingcomponent and the movable contact is narrow at the part that is near theshaft and is wider at the part that is far from the shaft, it ispossible to restrain the rotational position change of the movablecontact caused by the spinning of the shaft that fixes the center partof the movable contact. Thus, the contact position of the movablecontact points against the fixed contact points can be stable and thecurrent control by the electromagnetic switching device can be performedmore stably.

In the improved invention described above, it is preferable that thisinvention has a recess, which has an insertion hole on the other end ofsaid axis and is fixed at the bottom part of said enclosing component,on the bottom part, that a flange that rubs the inner surface of saidrecess in the direction of said axis is formed on the part of one of theends of said shaft, and that the insertion hole is made on the flange aswell as the valve that opens and closes the insertion hole. It is alsopreferable that said insertion hole is covered by inserting one of theends of the shaft including said flange in said insertion hole, and saidrecess is filled with gas, fluids or particles that become resistant tothe movement of said shaft along said axis.

In the improved invention described above, it is preferable that thisinvention has a mass body that vibrates along said axis by deformingelastically in at least one moving part in order to restrain themovement of the moving part that moves accompanying the movement of saidmovable iron core.

In the improved invention described above, it is preferable that thisinvention has a gap quasi-connected on the respective facing surfaces ofsaid first yoke and said movable iron core.

In the improved invention described above, it is preferable that thisinvention has an enclosure with fluids inside at the position where atleast one of the following collides: the movable iron core, the shaft,and the movable contact.

With this type of mechanism, it is possible to perform a suitablebraking for the discontinuation of the movement of the moving parts thatmove accompanying the excitation and non-excitation of theelectromagnetic actuator, and is also possible to obtain anelectromagnetic switching device that whose operating noise is quiet.

In the improved invention described above, it is preferable that thisinvention has a body that holds the main body of the electromagneticswitching device with said terminal area projected outward, and thatsaid body has mountings which have insertion holes to insert the fixingcomponent used to attach the body to the external mountings. It is alsopreferable that pipes made of high damping steel are inserted into saidinsertion holes and, with the pipes intervening, said body is fixed tothe external mountings by inserting the fixing component into theinsertion holes and the pipes on said mountings.

In the improved invention described above, it is preferable that thisinvention has a body that holds the main body of the electromagneticswitching device with said terminal area projected outward, and thatsaid body has mountings which have insertion holes to insert the fixingcomponent used to attach the body to the external mountings. It is alsopreferable that a flexible ring-shaped component that encloses themagnetic fluids, MR fluid or ER fluid is placed on the attaching side ofthe mountings, and with the ring-shaped component intervening, that saidbody is fixed to the external mountings by inserting the fixingcomponent into the insertion holes and the pipes on said mountings.

With this type of mechanism, it is possible to restrain the vibration ofthe electromagnetic switching device from transmitting to outside and tomake an operating noise quiet.

BRIEF DESCRIPTION OF THE DRAWINGS

(FIG. 1) Cross-section view on the plain surface indicating directions,right, left, top and bottom, of an electromagnetic switching deviceconcerning Embodiment 1 of this invention

(FIG. 2) Top view of the electromagnetic switching device without apotting process (FIG. 3) Cross-section view of line C-C of FIG. 2

(FIG. 4) Cross-section view of line A-A of FIG. 1

(FIG. 5) Broken-down perspective view of the electromagnetic switchingdevice

(FIG. 6) Perspective view of the electromagnetic switching devicewithout a potting process

(FIG. 7) Perspective view of the electromagnetic switching device

(FIG. 8) Cross-section view of line D-D of FIG. 1

(FIG. 9) Cross-section view on the plain surface indicating directions,right, left, up and bottom, of an electromagnetic switching deviceconcerning Embodiment 2 of this invention

(FIG. 10) Cross-section view of the adjacent part of a recess of theelectromagnetic switching device

(FIG. 11) Cross-section view of the adjacent part of a recess of anelectromagnetic switching device concerning embodiment 3 of thisinvention

(FIG. 12) Cross-section view of the adjacent part of a recess of anelectromagnetic switching device concerning Embodiment 4 of thisinvention

(FIG. 13) Cross-section view on the plain surface indicating directions,right, left, up and bottom, of an electromagnetic switching deviceconcerning Embodiment 5 of this invention

(FIG. 14) Cross-section view illustrating the movement of a first yokeand a movable iron core of the electromagnetic switching device

(FIG. 15) Graph of the variation of the magnetic force between the firstyoke and the movable iron core of the electromagnetic switching device

(FIG. 16) Cross-section view of the adjacent part of a recess of anelectromagnetic switching device concerning Embodiment 6 of thisinvention

(FIG. 17) Outside view or partial cross-section showing the attachmentof an electromagnetic switching device concerning Embodiment 7 of thisinvention

(FIG. 18) Outside view or partial cross-section showing the attachmentof an electromagnetic switching device concerning Embodiment 8 of thisinvention

(FIG. 19) Cross-section view of an existing electromagnetic switchingdevice

(FIG. 20) Cross-section view of line E-E of FIG. 19

(FIG. 21) Side view of the electromagnetic switching device

PREFFERED EMBODIMENT OF THE INVENTION

The electromagnetic switching devices concerning the embodiments of thisinvention are described referring to the Figures as follows. Thedirections, top and bottom, right and left, and front and back, in theFigures are referred to accordingly. In addition, the electromagneticswitching devices of this invention can be used in all the mountingdirections.

Embodiment 1

FIGS. 1 to 8 show the electromagnetic switching device of Embodiment 1.FIG. 1 is mainly referred to and the other figures are referred toaccordingly as below. The electromagnetic switching device 1, as shownin FIG. 1, has the electromagnetic actuator 2 that has the movable ironcore 22, the pair of fixed terminals 3 that respectively has the fixedcontact points 32, the movable contact 4 that has the movable contactpoints 41 on the right and left ends, the shaft 5, and the enclosingcomponent 6 that holds the movable contact points 41 and the fixedcontact points 32. The pair of movable contact points 41 respectivelycontact with and detach from the pair of fixed contact points 32, andthe pair of fixed contact points 32 are each respectively conducted byeach other or insulated again through the shaft 5 by the electromagneticactuator 2 moving the movable iron core 22 along the axis (hereafterreferred to as the direction of up and down or the axis that is placedvertically). The mechanism and the assembly of each component aresequentially described, and the movement of the electromagneticswitching device 1 is described subsequently.

The electromagnetic actuator 2 consists of the solenoid coil 21, thefirst and second yokes 23 and 24 that are placed one above the other,the movable iron core 22, etc. The solenoid coil 21 consists of thehollow bobbin 21 a, which has the flanges one above the other, with theconducting wire wound around it, and both ends of the conducting wireare led to the outside of the body 11. The first yoke 23 is placed fromthe middle of the inner circumference surface to the upper surface ofthe solenoid coil 21, the second yoke 24 is placed from the lower partof the inner circumference surface to the lower surface and the outercircumference surface of the solenoid coil 21, and these, the first yoke23 and the second yoke 24, form the magnetic gap that has the magneticpoles facing each other inside the solenoid coil as well as the magneticpath. (Refer to FIGS. 5 and 4 regarding the shape of the first andsecond yokes.)

The movable iron core 22 has a part of itself intervening in themagnetic gap mentioned above and has the rest of itself placed movablyup and down in the internal tube component of the second yoke 24. Also,the movable iron core 22 is biased to the direction such that themagnetic gap becomes larger (to the bottom) by the action of the coilspring. Therefore, when the solenoid coil 21 is excited, the movableiron core 22 moves up in order to lessen the magnetic gap, and when theexcitation is stopped, it moves down by the action of the coil spring 22a.

The fixed terminal 3 consists of a pair of conductors having fixedcontact points 32 on the lower end and the terminal area 31, whichconnects to the external circuit, on the upper end, and are placed onthe upper part of the enclosing component 6 separately to the right andleft sides. The groove, for example, is formed on the terminal area 31so that the external terminal can be fixed with screw nuts.

The movable contact 4 is built to have the movable contact points 41facing opposite to said fixed contact points 32 each respectively on theboth right and left ends of the rectangular shaped long conductive plateso that they contact and detach, and the middle part of it is fixedunder the retentive part 51 that is formed on the upper part of shaft 5.In other words, the upper surface of the movable contact 4 is pushed bythe guard part of the retentive part 51 and at the same time the bottomsurface is pushed up by the contact pressure springs 41 a and 41 b.

The shaft 5 is a rhabdom that is movable up and down within a specifiedrange along the central axis inside the electromagnetic actuator 2. Thelower end of the connecting axis 52 that extends downward from theretentive part 51 on the upper end is fixed into the movable iron core22, and the shaft 5 is placed on the central axis of the electromagneticactuator 2. The lowest limit of the movement of the shaft 5 is the pointwhere the diameter expansion part created by a stopper 53 such as theC-shaped ring, for example, and placed at the middle of the connectingaxis of the shaft 5 collides with the insertion hole 23 a on the centralaxis of the first yoke 23. The cushioning component 53 a is placed onthe collision point. Also, the upper limit of the movement is the pointwhere the upper end of the movable iron core 22 contacts with the lowerend of the first yoke 23.

The body 11 is made of a resin molding that has an opening on the upperside, and the main body of the electromagnetic switching device isplaced inside through the opening. The body 11 has the mountings 13 onthe both right and left sides in order to be attached to the attachingparts of other devices for the use of the electromagnetic switchingdevice 1. The body 11 is fixed to the external attaching part with screwbolts, nuts, etc. using the insertion holes 13 a that are formed on themountings 13.

The enclosing component 6 holds the movable contact points 41 and thefixed contact points 32. The enclosing component 6 is formed into a boxshape with an opening 61 on the lower side, and the fixed contact points32 side of the fixed terminal 3 is fixed by being inserted into theinsertion holes from the outside to the inside on the right and leftsides of the bottom part 62 (in the layout of the Figure, it is reversedand the bottom is up.) The enclosing component 6, for example, is madeof insulating materials such as mold resin and ceramics. On the outsidewall of the bottom part 62 of the enclosing component 6, the dividingwall 62 a is built to separate the terminal area 31 of the right side ofthe fixed terminal 3 from the left side of the fixed terminal 3spatially.

The enclosing component 6 has the guard part facing outward around theopening 61 and is fixed on the upper surface of the first yoke 23 withthe screws 63 a through the attaching holes at the four corners of theguard part (refer to FIG. 5) as shown in FIG. 2. In this state, aquasi-hermetically sealed space 63 is formed by the enclosing component6 and the first yoke 23. In the quasi-hermetically sealed space 63, thefixed contact points 32 and the movable contact points 41, in otherwords, the movable contact 4 which has the movable contact points 41,the shaft 5 which has the movable contact 4 and moves it up and down,and the accessories such as the contact pressure springs 41 a and 41 bare placed. In this quasi-hermetically sealed space 63, the fixedcontact points 32 and the movable contact points 41 contact with anddetach from each other and additionally the arc generated by thiscontact and detachment is extinguished.

Around the enclosing component 6, the pair of permanent magnets 65 arefixed by the yoke 64 for forming the magnetic path, and are placed sothat the enclosing component 6 is put between them as shown in FIGS. 2and 3. These permanent magnets 65 are placed with the magnetic polesfacing each other in order to quickly extinguish the arc, which isgenerated when the fixed contact points 32 and the movable contactpoints 41 contact and detach, by the magnetic field of the permanentmagnet.

Each component in FIG. 5 mentioned above is respectively assembled bythe specified procedures and becomes the main body of theelectromagnetic switching device 10 as shown in FIG. 6, excepting thebody 11. The main body of the electromagnetic switching device 10 isplaced in the body 11, and the potting compound 12a is charged into thespace 12 between the main body of the electromagnetic switching device10 and the body 11 as shown in FIG. 7.

Subsequently, the following three points on the mechanism of theelectromagnetic switching device I mentioned above are describedaccordingly: (1) the up and down movement of the movable iron core 22and the movement of the contacting and detaching of the fixed contactpoints 32 and the movable contact points 41 accompanying this up anddown movement, (2) the function of the quasi-hermitically sealed space63 and the mechanism of the potting compound 12 a, and (3) the relationbetween the internal measurement of the enclosing component 6 and themovable contact 4.

(1) Refer to FIGS. 1 and 3. When the electromagnetic actuator 2 isexcited and the movable iron core 22 moves up, the shaft 5 and themovable terminal 4 move up together, and when the movable contact points41 touch the fixed contact points 32, the movable contact 4 stops movingand the shaft 5 continues to move upward until the movement of themovable iron core 22 stops (overstroke.) In this state, the movablecontact points 41 are press-contacted with the fixed contact points 32by the biasing power of the contact pressure springs 41 a and 41 b, andthe electric resistance between the contact surfaces is sufficientlyreduced.

The contact pressure spring 41 a placed on the upper part is a weak coilspring (the spring constant is low) and the contact pressure spring 41 cplaced on the lower part is a strong coil spring (the spring constant islarge.) These two strong and weak coil springs are separated by thestopper 41 b, which has a part projecting upwards, and used in seriesvertically. With this type of mechanism, the contact pressure spring 41a, which is a weak coil spring, is compressed until the projecting parton the edge of the, stopper 41 b touches the under surface of themovable contact 4, and after the projecting part on the edge touches themovable contact 4, only the contact pressure spring 41 c, which is astrong spring, is compressed.

In such an electromagnetic switching device 1, it is possible torestrain the occurrence of the performance trouble called hesitationthat occurs when the difference between the magnetic attractive forceand the spring load becomes small. In addition to this effect, it isalso possible to decide the stroke of the contact pressure springs 41 aand 41 c by using the stopper 41 b and to prevent the spring load fromvarying.

(2) Refer to FIGS. 1 and 3. The potting compound 12 a is charged intothe space between the body 11 and the main body of the electromagneticswitching device, which is the space between the body 11 and thequasi-hermitically sealed space 63. By using a material that has a goodheat conductance as the potting compound 12 a, it is possible to quicklycool down the enclosing component 6 and the first yoke 23 that are theconstructional components of the quasi-hermitically sealed space heatedby the arc generated between the fixed contact points 32 and the movablecontact points 41. Therefore, it is possible to extinguish the arc byquickly absorbing the heat energy of the arc generated. Additionally,because the potting compound 12 a restrains the propagation of thevibration that occurs from the main body electromagnetic switchingdevice, which is placed inside, to the body 11, a silent effect can beobtained. By using the potting compound 12 a, the covering component isnot needed and the body 11 can be built with only one component. Thisenables the lowering of costs.

(3) Refer to FIG. 8. The inside walls of the front and back (top andbottom directions in the Figure) of the enclosing component 6 arethicker towards the inner side in the middle part, and the measurementsbetween the inside walls are d2 for the distance of the middle part, d3for the distance of the edge part, and the relation with d1 for thewidth of the front and the back of the movable contact 4 is d1≈d2<d3.When the distance between the inside walls of enclosing component 6 andthe movable terminal 4 is narrow at the part that is near the shaft andwider at the part that is far from the shaft, it is possible to limitthe rotational position change of the movable contact due to thespinning of the shaft, etc. that fixes the center part of the movablecontact 4. Thus, the contact position of the movable contact points 41against the fixed contact 32 can be stable, and the current control bythe electromagnetic switching device 1 can be performed more stably.Subsequently, the Embodiments from 2 to 8 described below add functionsto reduce the operating noise of the electromagnetic switching device tothe electromagnetic switching device of Embodiment 1.

Embodiment 2

FIGS. 9 and 10 show the electromagnetic switching device 1 in Embodiment2. This electromagnetic switching device 1 has a recess 8 with aninsertion hole 81 facing downward at the center of the bottom part 62 ofthe enclosing component 6, and the point that the upper part of theshaft 5 is inserted and closes the inserting hole 81 is different formthe electromagnetic switching device 1 in Embodiment 1 (for instance,refer to FIG. 1.) When the top part of the shaft 5 moves up and down,gas, fluids or particles that become resistant to the up and downmovement of the shaft fill the recess 8.

In Embodiment 2 of this mechanism, it is possible to reduce the impactgiven when the movable contact points 41 contact with and detach fromthe fixed contact points 32 by the resistance of the gas, fluids orparticles to the movement of the shaft 5, and to reduce the operatingnoise of the electromagnetic switching device 1. Additionally, becausethe resistance of the gas, fluids or particles does not work exceptingwhen the movable contact points 41 contact with and detach from thefixed contact points 32, the excess power is not applied constantly, andthere is no occurrence of performance deteriorations (side effects) suchas a deterioration of the resistance to the vibration of theelectromagnetic switching device 1 and an increase of the drive voltage.

As mentioned above, the reduction of the operating noise of theelectromagnetic switching device 1 is achieved by appropriatelyrestraining the movements of the shaft 5, which is the moving part thatmoves accompanying the movement of the movable iron core 22, the movablecontact 4 and the movable iron core 22 itself (these we will name themthe movable part M generically). In other words, in general, thecushioning component that restrains the movement can be placed on themovable part M. Also, the recess 8 filled with the resistive fluids (gasand fluids or the particles) realizes this cushioning part. Therefore, acushioning part like this can be placed not only in the enclosingcomponent 6 as above but also at the parts which restrain the movementof the movable iron core 22 at the lower part. In addition, inEmbodiments 3 and 4 described below, the recess 8 is placed in theenclosing component 6.

Embodiment 3

FIG. 11 shows the recess 8 of the electromagnetic switching device 1 inEmbodiment 3. The electromagnetic switching device of Embodiment 3 formsthe flange 54, which rubs upward and downward along the inner surface ofthe recess 8, on the upper end of the shaft 5, and it has a valve 58that opens and closes the insertion hole 57 over the flange 54 as wellas the insertion hole 57 on the flange 54, and the upper end of theshaft 5 including the flange 54 is inserted into the insertion hole 81and closes the insertion hole 81, and the gas, fluids or the particlesthat become resistant to the movement of the shaft 5 along the axisplaced vertically.

In Embodiment 7 of the mechanism mentioned above, when the shaft 5 movesupward, it is possible to reduce the moving speed of the movable contact4 because of the resistance of the gas, fluids or the particles in therecess 8. On the other hand, when the shaft 5 moves downward, it is notpossible to slow down the moving speed of the movable contact 4 becausea valve 58 opens. Generally, when the movable contact 4 moves in adirection that the movable contact points detach from the fixed contactpoints, the moving speed is reduced, and the performance of theelectromagnetic switching device 1 is reduced, but in Embodiment 3,because opening the valve 58 prevents the moving speed of the movablecontact 4 from slowing down, it is possible to reduce the operatingnoise without deteriorating the performance of the electromagneticswitching device 1.

Embodiment 4

FIG. 12 shows the recess 8 of the electromagnetic switching device 1 inEmbodiment 4. The electromagnetic switching device 1 of Embodiment 4 hasthe enclosure S3, in which fluid is enclosed, at the position where atleast one of the following movable part M collides: the movable ironcore 22, the shaft 5 and the movable contact 4. In the electromagneticswitching device 1 shown in FIG. 12, the torus-shaped enclosure S3 witha hole in the center is fixed in the insertion hole 81 of the recess 8,and intervenes between the insertion hole 81 and the top of the upperend of the shaft 5. And the flange 54 is placed on the edge of the shaft5 inside the recess 8, and a flange (diameter expansion part) 55 is alsoplaced on the shaft 5 outside the recess 8.

In Embodiment 4 of the mechanism mentioned above, because the enclosureS3 moves to the inside and the outside of the recess 61 by being pushedby the flanges 54 and 55 when the shaft 5 moves up and down, it ispossible to absorb the impact generated when the movable part collides,using the viscosity of the fluid inside the enclosure S3 and also toreduce the operating noise.

Embodiment 5

FIGS. 13, 14 and 15 show the cross-section surface of theelectromagnetic switching device 1, the mechanism of the magnetic poles,facing each other, of the first yoke 23 and the movable iron core 22 ofthe electromagnetic switching device 1, and the change of the magneticpower between the magnetic poles, respectively in Embodiment 5. Theelectromagnetic switching device 1 of Embodiment 5 has a gap that has aquasi-connection on the respective facing surfaces of the first yoke 23and the movable iron core 22, in other words, it has a concave part 23 con the first yoke 23 and a convex part 22 c on the movable iron core 22.Additionally, the side of the concavoconvex gap can also be ataper-shaped surface, not only the vertical surface shown in FIG. 14.

In Embodiment 5 of the mechanism mentioned above, the reduction of themagnetic attractive force, which is generated when the magnetic flux Fdeviates from the direction of the movement of the movable iron core 22,is used when the mutual distance X of each facing surface of themagnetic poles changes from the situation whereby the mutual distance Xis wider than the gap as shown in the left side of FIG. 14 to thesituation whereby the mutual distance X is narrower than the height ofthe gap and interdigitates mutually shown in the right side of FIG. 14.

Refer to FIG. 15 for the explanation. The X-axis shows the movingdistance of the movable iron core 22 (the downward direction is positivein FIG. 13.), and the vertical axis shows the spring load Fs (springbiasing power) and the magnetic attractive force Fm. The spring load Fsbiases the movable iron core 22 to the positive direction of X and themagnetic attractive force Fm biases to the negative direction of X. X=0is the point where the movable iron core 22 reaches the movement limit(the highest point) by the magnetic absorption. X=X1 is the point wherethe movable iron core 22 returns to the maximum (the lowest point) bythe coil spring 22 a because of the excitation by the electromagneticactuator being stopped. X=X2 is the point where the fixed contact pointsand the movable contact points contact and detach.

The distance L1 is the distance between the contact points, and thedistance L2 is the distance of the overstroke, in other words, it is thedistance to give the biasing power, which is caused by the contactpressure springs 41 a and 41 b because of the shaft 5 rising even afterthe contact points contact with each other, to the distance between thecontact points. To the spring load Fs, only the coil spring 22 acontributes in the interval of X1-X2 and the contribution of the contactpressure springs 41 a and 41 b is added as well as the contribution ofthe coil spring 22 a in the interval of X2=0.

When a magnetic attractive force Fm that is larger than the spring loadFs is generated by the electromagnetic actuator being excited, themovable iron core 22 moves from X=X1 to X2, and the magnetic attractiveforce Fm increases accompanying the approach between the magnetic poles.The movable iron core 22 moves further to X=0 because of the increase ofthe magnetic attractive force Fm that exceeds the increase of the springload Fs. When the surface of the magnetic pole end is the normal shape(Embodiment 1), the magnetic attractive force Fm changes like the curveline d, but in the case of Embodiment 5, the attractive force decreasesimmediately before the movable iron core 22 colliding with the firstyoke 23 like the curve line e because of the gap effect as mentionedabove. With this, it is possible to absorb the impact generated when themovable contact points 41 collide with the fixed contact points 32 andto reduce the operating noise of the electromagnetic switching device 1.

Embodiment 6

FIG. 16 shows the surrounding part of the movable iron core 22 of theelectromagnetic switching device 1 in Embodiment 6. The electromagneticswitching device 1 in Embodiment 6 is built by adding a mass body (aweight) m, which vibrates along the moving direction of the movable partM by the elastic deformation, to at least one of the movable part M,which includes the movable iron core 22, the shaft 5 and the movablecontact 4. FIG. 16 shows the state that the storage frame 294, whichcontains the mass body m locked by the coil spring 295, is attached tothe shaft 5 as the movable part M.

When the mass of the movable part M is designated as M, the mass of themass body m is designated as m, and the mass body is rigidly fixed tothe movable part M, the movable part M with the mass body m collidekeeping the kinetic energy E1=½×(M+m)×V×V that is the basis of the speedV before the collision at the time of the movable contact points 41 andthe fixed contact points 32 colliding. However, in this Embodiment 6,because the mass body m that is vibratile and is fixed to the movablepart M continues to move with the kinetic energy of ½×m×V×V after thecollision, the vibration energy consumed by the collision is reducedfrom E1 to E2=½×M×V×V. Because of this, it is possible to reduce theoperating noise when the electromagnetic switching device drives.

Embodiment 7

FIG. 17 shows the condition of attaching the electromagnetic switchingdevice 1 to the external mountings in Embodiment 7. The electromagneticswitching device 1 in Embodiment 7, for example, is attached to anattaching part 9 such as a mounting plate of an electric vehicle throughthe mountings 13 that have the insertion holes 13 a formed on the body11. At this time, the pipes 14, which are made of high damping steel,are formed into a cylinder, and have the flange facing out on one of theends, are inserted into the insertion holes 13 a, and with the pipes 14intervening, the volt B, which is the fixing component, is inserted intothe insertion holes 13 a on the mountings 13, and the body 11 is fixedto the attaching part 9 using the nut N, which is one of other fixingcomponents. In Embodiment 7, because it is possible to reduce thevibration that propagates from the electromagnetic switching device 1 tothe attaching part 9, the operating noise of the electromagneticswitching device 1 can be reduced.

Embodiment 8

FIG. 18 shows the condition of attaching the electromagnetic switchingdevice 1 to the external mountings in Embodiment 8. The electromagneticswitching device 1 in Embodiment 8, for example, is attached to theattaching part 9 such as a mounting plate of an electric vehicle throughthe mountings 13 that have the insertion holes 13 a formed on the body11 in a same way as Embodiment 7. At this time, on the attaching side ofthe mountings 13, the flexible ring-shaped component 15 that enclosesthe magnetic fluids, MR fluid or ER fluid is placed, and with thering-shaped component 15 intervening, the volt B, which is the fixingcomponent, is inserted into the insertion holes 13 a or the ring-shapedcomponent 15 on the mountings 13, and the body 11 is fixed to themountings 9 using the nut N, which is one of other fixing components.

When the fluid enclosed is the magnetic fluid or MR fluid, thering-shaped component 15 becomes hard by the magnetic field at the timeof the electromagnetic actuator 2 being energized, and becomes softer atthe time of the electromagnetic actuator 2 being not energized than atthe time of the electromagnetic actuator 2 being energized. Also, whenthe fluid enclosed is ER fluid, the ring-shaped component 15 becomesharder at the time of the electromagnetic actuator 2 being energizedthan at the time of the electromagnetic actuator 2 being not energizedbecause the voltage is applied to ER fluid. And when the electromagneticactuator 2 is not energized and the voltage applied to ER fluid isremoved, it becomes softer than when the electromagnetic actuator 2 isenergized.

In Embodiment 8 as above, it is possible to reduce the operation noiseby having the ring-shaped component 15. Also, because it is possible tomake the ring-shaped component 15 harder when the electromagneticactuator 2 is energized, and softer when the electromagnetic actuator 2is not energized, it is suitable for electric vehicles. In other words,because the electric vehicle is stopped and the ring-shaped component 15is softer before the movable contact points 41 contact with the fixedcontact points 32, it is possible to restrain the propagation of thevibration to the attaching part 9 of the electric vehicle when themovable contact points 41 contact with the fixed contact points 32.Additionally, it is possible to prevent the resonance by fixing theelectromagnetic switching device 1 tightly to the attaching part 9 whilethe vehicle is moving, and the ring-shaped component 15 becomes softerafter the movable contact points 41 separate from the fixed contact 32points. Therefore, it is possible to restrain the propagation of thevibration to the attaching part 9.

This application claims a priority based on the Japanese PatentApplication No. 2003-270346 of Jul. 2, 2003. The entire content of theapplication is incorporated herein by reference.

1. An electromagnetic switching device, comprising: an electromagneticactuator which has a solenoid coil wound around an axis and having ahollow part on the axis, a movable iron core placed movably in saidhollow part along said axis, a first yoke placed on one of the ends ofsaid solenoid coil, facing one of the ends of said axis and having theinsertion hole above said axis, and a second yoke placed on the otherend of said solenoid coil and facing the other end of said axis; a pairof fixed terminals, which respectively have the fixed contact points onone of the ends of said axis as well as the terminal area connected tothe external circuit respectively on the other end of said axis; amovable contact, which has a pair of movable contact points on the bothends that respectively contact with and detach from said fixed contactpoints; a shaft, which has the connecting axis that is fixed to theretentive part that retains said movable contact, that extends from thisretentive part to the other end of said axis, that is inserted throughthe insertion hole of said first yoke, and that is fixed to said movableiron core; and an enclosing component, which said movable contact pointsand said fixed contact points are placed in, wherein the pair of saidmovable contact points respectively contacts with and detaches from thepair of said fixed contact points through said shaft by moving saidmovable iron core up and down along said axis using said electromagneticactuator, the enclosing component is formed into a box shape with anopening on the other side of said axis, each side of the fixed contactpoints of the pair of said fixed terminals are inserted from the bottompart of the enclosing component and are fixed, the quasi-hermeticallysealed space is formed by the enclosing component and at least saidfirst yoke, and said movable contact points and said fixed contactpoints are placed in the quasi-hermetically sealed space.
 2. Anelectromagnetic switching device according to claim 1, wherein it has abody that holds the main body of the electromagnetic switching devicewith said terminal area projecting outward and that has a pottingcompound charged into a space between said body and saidquasi-hermetically sealed space.
 3. An electromagnetic switching deviceaccording to claim 1, wherein a distance between an inside wall of saidenclosing component and said movable contact is narrow at the part thatis near said shaft, and is wider at the part that is far from saidshaft.
 4. An electromagnetic switching device according to claim 1,wherein it has the recess, which has the insertion hole on the otherside of said axis and is fixed at the bottom part of said enclosingcomponent, on the bottom part; the flange that rubs the inner surface ofsaid recess to the direction of said axis is formed on the part of oneof the ends of said shaft, and the insertion hole is made on the flangeas well as the valve that opens and closes the insertion hole; saidinsertion hole is covered by inserting one of the ends of the shaft,which includes said flange, through said insertion hole; and said recessis filled with the gas, fluids or particles that become resistant to themovement of said shaft along said axis.
 5. An electromagnetic switchingdevice according to claim 1, wherein it has a mass body, which vibratesalong said axis by elastically deforming, in at least one moving part inorder to restrain the movement of the moving part that movesaccompanying the movement of said movable iron core.
 6. Anelectromagnetic switching device according to claim 1, wherein it has agap that has a quasi-connection between the respective facing surfacesof said first yoke and said movable iron core.
 7. An electromagneticswitching device according to claim 1, wherein it has an enclosure withfluids inside at the position where at least one of the followingcollides: said movable iron core, the shaft or the movable contact. 8.An electromagnetic switching device according to claim 1, wherein it hasa body that holds the main body of the electromagnetic switching devicewith said terminal area projected outward; and said body has themountings with insertion holes to insert a fixing component used toattach the body to the external mountings, pipes made of high dampingsteel are inserted into said insertion holes, and with the pipesintervening, said body is fixed to the external mountings by insertingthe fixing component through the inserting holes or the pipes on saidmountings.
 9. An electromagnetic switching device according to claim 1,wherein it has a body that holds the main body of the electromagneticswitching device with said terminal area projected outward; and saidbody has the mountings with the insertion holes to insert the fixingcomponent used to attach the body to the external mountings, a flexiblering-shaped component that encloses the magnetic fluids, MR fluid or ERfluid is provided on the attaching side of the mountings, and with thering-shaped component intervening, said body is fixed to the externalmountings by inserting the fixing component through the insertion holesor the pipes on said mountings.